The primary language is German, but basic English is generally understood in most big cities. The official currency in Germany is EURO.

Transport: For reliable fast long distance transport in and out of Germany, you should choose the Deutsche Bahn (German Rail). Stick to the more expensive Intercity or ICE connections for longer distances, since the slower and cheaper "express" trains will generally stop for a few minutes in each and every town on the way, and this means your average speed will rarely exceed 60km/h.
The buses are usually much cheaper, but the travel time is longer.
Pro tip: You can get cheap train tickets if you travel over the weekend.

Avoid planes for trips inside Germany. The cheap tickets (ryanair) usually depart and land on some smaller airports 20km out of town to avoid the high fees for landing on international airports, and this means you have to pay extra for the bus or train to get to and from to Airport, and by adding up those extra costs and travel times you will in most cases not save any time or money compared to the train.